Trends in the frequency of extreme climate events in Latvia

This study investigated the long-term variability of extreme climate event indicators in Latvia. To assess trends in the frequency of extreme climate events, 14 extreme climate indices, such as number of extremely hot days, number of frost days or number of days with heavy precipitation, were calculated and compared with other indices characterizing mean climate. Trend analysis of long-term changes in the frequency of extreme climate events demonstrated a significant increase in the number of meteorological events associated with an increased summer temperature (for example, the number of summer days and tropical nights) and a decrease in the number of events associated with extreme temperature events in winter (the number of ice days and frost days). Due to the decreasing number of cold days, under the changing climate, the length of the growing season has increased. There were also increases in the number of days with heavy precipitation and in the intensity of heavy precipitation. Finally, influences of the large-scale atmospheric circulation on the occurrence of climate extremes are discussed.